The Mamiya C330, my main camera, is a thing of pure beauty. In my opinion, it's the best twin lens reflex camera ever built. There are many reasons for this claim. Firstly, it is one of the only TLR with interchangeable lenses. All of them are super sharp. I mainly use the 105mm DS lens, since it has a depth of field preview feature that other Mamiya TLR lenses don't have. It's slightly telephoto, but still considered to be a "normal" focal length lens. When my 105mm can't handle my subject, I have a variety of other great lenses to choose from. I own the 55mm, 65mm, 80mm, 105mm, 135mm, and 180mm lenses. The only lens I'm missing is the 250mm lens. Someday I'll buy it... someday.
Another great feature of the C330 is the parallax correction bar in the viewfinder. As you focus closer, a small bar on the left-hand side of the finder moves down, showing you where the top of the image will cut off. You then simply move the camera upwards the necessary distance, and you're good to go. This awesome feature makes close-ups much less of a pain in the ass.
This leads me to explain why I choose to use a Twin Lens Reflex, when there are so many great medium format SLR's out there. Here are my 3 main reasons for using TLR's, specifically my C330.
1. It's simpler. A TLR has less that can go wrong. There is no moving mirror, and no focal plane shutter. The shutter is in each individual lens, so if something goes wrong with the shutter, you can get the lens repaired and still have your camera to work with.
2. No mirror slap. I do a lot of long exposures, and not having a giant mirror (look at the Pentax 6x7) slapping up and down makes sure the camera stays perfectly still during exposure.
3. Filters. I often use yellow, red, and sometimes green filters in my photography. It's great to have a filter attached to the taking lens and not have to compose the image while having everything look red. It makes framing and focusing so much easier with filters.
So, now that I've bored you, take a look at a few photos I have taken with my Mamiya C330.